1. Field of the Invention
This invention pertains generally to vehicle safety devices and more particularly to a system and method for reducing vehicular rear-end collisions by the early sensing of events such as hard brake pedal activation and the communication of the said events to approaching vehicle so as to provide a reaction time advantage to drivers therein.
2. Description of the Background Art
Rear-end collisions on our highways are a major cause of serious injury. The incidence of rear-ends collisions has risen rapidly as our highway systems get increasingly congested. The bulk of these rear end collisions could be avoided, it is estimated by the National Highway Traffic Safety Administration (NHTSA) that about 88% of rear end collisions in the United States are caused by vehicles following too closely, and/or coupled with driver inattention. Further, it is estimated that rear-end collisions represent approximately 28% of all vehicle collisions nationwide. Rear-end collisions account for 36% of fatal and injury collisions in the state of California.
Drivers have been admonished and given a variety of guidelines for following distance, however, these have done little to alter driving habits. Drivers on the highway are often jockeying for position, and some feel that when attempting to follow at a “safe distance”, the space just quickly fills with one or more vehicles. Unfortunately, when vehicles closely follow one another there is often insufficient time for a driver to respond to a situation and come to a stop prior to rear-ending the vehicle ahead. In existing vehicles, drivers are unable to gain sufficient information relating to the action of drivers and conditions farther up the road. Drivers may watch brake lights come on and go off again as they try to see what is occurring farther up the road. Often the view up ahead is obscured, or completely blocked, by the vehicle ahead, leaving the driver reliant on being extremely alert and having fast reaction times. Unfortunately drivers are also relying on luck which can run out at any time when the person ahead unexpected “slams” on the brakes. Under actual driving conditions, by the time a driver recognizes a “situation” they often have insufficient time to slow, or stop, in order to prevent colliding with another vehicle. Coming to a stop from highway speeds can require 3–4 seconds during which over 200 hundred feet of highway may be traversed. At highway speeds, every 1/100th of a second that a driver delays in applying their brakes can translate to another foot of highway. The energy for these additional feet are often absorbed by the rear end of another vehicle. In many cases significant injuries may be prevented by decreasing reaction times by a few hundred milliseconds.
Another source of major rear-end accidents occurs within multi-car “pile-ups”, where at times, over a hundred vehicles have been known to crash in a chain-reaction of rear-end collisions. These “pile-ups” are generally attributable to low visibility conditions which further reduce driver reaction time; by the time the problem is visually seen, there is not enough time to react at the speed being driven and another car is added to the pile of wreckage with additional lives often being lost.
Drivers have been continually admonished not to tailgate. Drivers know that they should not follow any closer than one car length for every 10 miles per hour of speed. Many drivers are also cognizant of the guidelines for driving in reduced visibility. Unfortunately under actual driving situations these driving guidelines appear to be widely ignored by drivers. Drivers push along trying to rely on their wits and reactions to save them from getting into an accident. Yet, given the wrong set of circumstances they will simply not be able to stop in time. Driver attitudes have been mentioned here because the success of any system or method attempting to reduce highway mortality must take driver attitudes and driving patterns into account. The rule of “one car length per 10 mph” is a simple system that technically works—however it totally ignores prevailing highway conditions and driver attitudes, and therefore is largely being ignored. More recently drivers have been directed to follow the “3 second rule”, wherein drivers should follow the car ahead no less than 3 seconds. Again, the 3 second rule—if followed—would save lives. Unfortunately, drivers rarely follow such guidelines. Any system and method that is to have a wide range effect to lower the collision rate will be required to do so under prevailing highway conditions and driver attitudes.
Presently, the only alert provided by vehicles to approaching traffic is the brake light. It is interesting to note how the size and intensity of brake lights has increased over the years. In order to enhance recognition and driver response, brake lights have been made larger and brighter, while auxiliary deck mounted brake lights have been incorporated within vehicles. So important is quick recognition of braking that in fact it is a standard policy among numerous insurance companies to provide discounts for vehicles which incorporate the additional centrally mounted brake light. However, due to the still limited information conveyed, and coupled with the constant on/off flicking of brakes in traffic, a driver's reaction to seeing the brake lights come on one more time is rarely one of jumping to engage their own brakes. However, in many cases that reaction would be the only one capable of preventing an accident.
Numerous concepts have been considered for reducing rear-end collisions. The thought of computer driven automobiles, which control their own speed has perhaps been around since the advent of the first microcomputers. Programs at various automobile manufacturers, and universities have been testing elements of the concept for a number of years. However, wresting control of a vehicle from the driver is an approach that not only ignores driver attitudes, but ignores the complex dynamics that exist with highway driving. Recognizing the distance of objects or close vehicles on the road is already a function that the driver performs; drivers know how close they are, they just don't know when the driver ahead will “slam” on the brakes or swerve suddenly.
A huge variety of technical solutions can be arrived at which would theoretically reduce traffic accidents, however, in order to reduce actual traffic accidents any system or method needs to gain widespread use on the highway system. The system or method, therefore, needs to be designed with regard to the difficulties involved with gaining widespread acceptance and standardization. Any system or method that is to be successful at reducing traffic fatalities and injuries should in addition take into account present vehicle designs, the current highway infrastructure, the design differences between various manufactured vehicles, design cost, manufacturer liability, the cost of testing, reliability concerns, and implementation cost. Additionally, the results from the system or method should be capable of being progressively achieved. Implementations that can not be achieved in progressive steps, can require too large of a commitment from consumers, manufacturers, and government regulators.
As can be seen, therefore, the development of a system and method capable of sufficiently reducing driver reaction time could save thousands of lives, and eliminate or reduce untold injuries. Unfortunately, getting any system or method into widespread use is a complex issue. A safety system directed at widespread adoption must take into account actual highway driving patterns while it must be reliable and yet capable of inexpensive deployment.
So far societies' best implemented solutions involve accepting crashes and then protecting drivers with better restraint systems, crumple zones, and airbags. These protection solutions are wonderful for unavoidable accidents, yet statistics indicate that a vast majority of accidents can be avoided. These accidents can be avoided if enough reaction time advantage can be provided to drivers. The rear-end vehicle collision reduction system of the present invention is directed at providing solutions which provide this reaction time advantage while attempting to take into account the needs and attitudes of drivers, manufacturers and government regulators.